1. Field of the Invention
The disclosure relates to an image formation apparatus such as a printer using an electrophotographic process or a facsimile apparatus, and a method of adjusting a developer discard amount for the same.
2. Description of Related Art
Some image formation apparatuses employ a method in which: a surface of a photosensitive drum is evenly charged by a charging device and is exposed to light by an exposure device to form an electrostatic latent image thereon; a toner image is formed on the photosensitive drum by developing the electrostatic latent image with a development device; and then the toner image is transferred on a recording medium and is further fixed thereon. In such image formation apparatuses, a toner discard operation is carried out for the purpose of suppressing a degradation in print image due to deteriorated toner left on a development roller and maintaining high image quality. As described in Japanese Patent Application Publication No. 2004-125829, for example, a toner discard operation includes discarding deteriorated toner on the development roller by forcibly attaching the toner on the development roller to the photosensitive drum when the number of image dots printed during a prescribed number of rotations of the photosensitive drum is smaller than a predetermined threshold.